Quants section - Challenge problems only, understand, difficulty, challenge

JGovender

Hi there,
For those who are using/have used Schwesser notes…
Are the “Challenge Problems” actually part of the exam? I mean, as far as I know the CFA exam is not only about difficulty, but also about time, appart from being only multiple-choice (at least lev 1). I am going through the Quants section and finding the challenge problems very challenging, time consuming, and with practical or written solutions… Should I focus on that problems or just try to understand the main ideas?
Thank you all in advance.